The present invention relates to shock compensating apparatus in general, and more particularly to improvements in apparatus which can be utilized with advantage to compensate for fluctuations of torque which is transmitted by the output element of an internal combustion engine. Still more particularly, the invention relates to improvements in apparatus which can be utilized in motor vehicles to compensate for fluctuations of torque transmission between the crankshaft of an internal combustion engine and the input shaft of a change-speed transmission.
It is well known to transmit torque from the crankshaft of an internal combustion engine to the input shaft of a change-speed transmission in a motor vehicle by means of a composite flywheel, one section of which rotates with the crankshaft and the other section of which rotates with the input shaft or can be coupled thereto by a friction clutch. The two sections of the composite flywheel can turn relative to each other within certain limits against the opposition of one or more vibration dampers. As a rule, one of the flywheel sections is rotatably journalled directly on the other flywheel section by means of one or more antifriction bearings. Reference may be had, for example, to commonly owned copending patent application Ser. No. 669,657 filed Nov. 8, 1984 by Oswald Friedmann.
The placing of a plain or antifriction bearing between the two sections of a composite flywheel brings about a number of serious drawbacks which are attributable primarily to the fact that the two sections merely have a rather limited freedom of angular movement relative to each other. This is particularly undesirable when the vehicle which embodies such composite flywheel is under load and the one and/or other flywheel section turns back and forth at a very high frequency but within a small or extremely small angle which is, or can be, much less than one degree. Such high-frequency but low-amplitude angular displacements of the two flywheel sections relative to each other entail very pronounced wear upon the plain or antifriction bearing or bearings. Moreover, the lubricating action upon the contacting surfaces of the plain bearing(s) or upon the areas of contact between the races and the rolling elements of the antifriction bearing(s) is highly unsatisfactory because the extent of angular movement between the contacting surfaces or between the races and rolling elements is very small. Furthermore, and if the bearing assembly between the two sections of the flywheel comprises one or more antifriction ball or roller bearings, the rolling elements apply to relatively small portions of the tracks of the respective races extremely pronounced and highly localized stresses which entails rapid destruction of the races as a result of the development of unevennesses in the form of recesses or grooves. Moreover, repeated rolling of each ball or an otherwise configurated rolling element along the adjacent small portion of the respective race or races results in chipping of the races whereby the material which is separated from the race or races leaves cracks or cavities with attendant rapid deterioration of and total destruction of the entire bearing or bearings.